The university, in Oakland, Calif., offers training classes to people seeking to become legal medical marijuana providers under California state law.

"Clearly, they're trying to knock down one of the leaders in the cannabis reform movement," Oaksterdam Executive Chancellor Dale Sky Jones said.

While both sides debate the legality and necessity of the raid, a Twitter user going by the name "Octal," snapped a picture of what he claims is a van with expired tags used by agents in the raid. In the tagline below his picture, Octal writes, "The DEA agents raiding oaksterdam are in vans with expired tags."

In a 2010 executive order, then-California Governor Arnold Schwarzenegger declared illegal possession of up to an ounce of marijuana an "infraction," punishable by up to a $100 fine.

Conversely, the fine for expired tags in California is only $10 but the associated fees with the DMV can go as high as several hundred dollars.

Oakland is widely viewed as one of California's most pot-friendly cities. A 2004 Oakland medical marijuana initiative, approved by 65 percent of voters in 2004, designated the investigation, citation and arrest of illegal marijuana offenses to be the city's "lowest law enforcement priority."